A conventional manufacturing system of display panels is designed to use rectangular film sheets which are preliminarily cut in a separate process and transported in the form of a package to a manufacturing line of display panels. As disclosed in the Japanese Laid-Open Patent Publication 2002-23151A, such rectangular film sheets are produced in a film sheet manufacturing apparatus by being punched out or cut from a continuous web of film laminate including a polarizing film. Herein, these film sheets are collectively referred as “individualized film sheets.” A plurality of such individualized film sheets are brought into the display panel manufacturing line. The individualized film sheets thus brought into the manufacturing line are stored in a magazine provided for storing the individualized film sheets. Each of the individualized film sheets generally comprises an adhesive layer applied to the film sheet and a peelable film for protecting an exposed surface of the adhesive layer.
The magazine storing the individualized film sheets is incorporated in the display panel manufacturing line. The rectangular panels are taken out one-by-one from a magazine storing rectangular panels, which is similarly incorporated in the manufacturing line. The individualized film sheets are taken out from the magazine one-by-one typically by means of a suction type conveyance unit in synchronization with the rectangular panels. The peelable film is peeled from each of the taken out individualized film sheets to have the adhesive layer of the film sheet exposed. The individualized film sheets with the adhesive layers in the exposed state are conveyed under suction to the lamination or attachment position for lamination or attachment to the rectangular panels. Aligning the individualized film sheets respectively with the rectangular panels is generally performed by conveying the individualized film sheets to respective one side surfaces of the respective rectangular panels.
In contrast to the display panel manufacturing system using such individualized film sheets, the Japanese Patent No. 4371709B discloses a display panel manufacturing system wherein film sheets having substantially the same length as the rectangular panels are formed on a peelable film, the peelable film being then moved to convey the film sheets to the lamination or attachment position for lamination with the rectangular panels, the film sheets being then adjusted for alignment and laminated with the rectangular panels. More particularly, there is disclosed a display panel manufacturing system wherein film sheets are formed on a continuous web of a continuous strip shaped film laminate which is taken out from a roll of a strip shaped film laminate provided in the display panel manufacturing system, and conveyed to a lamination position for lamination with rectangular panels, the film laminate having a width which is substantially the same as that of the rectangular panel, the film sheets being formed by providing the continuous web with transversely extending, longitudinally spaced slit lines and attached to the rectangular panels. The manner of aligning the film sheets with the rectangular panels is such that a rectangular panel conveyed to the lamination position is positioned at its end face, in accordance with information of detected position of the leading edge of a film sheet, so that the end face of the rectangular panel is aligned with a corresponding end face of the film sheet.
The Japanese Patent No. 4377964B notices that it is difficult to accurately feed a continuous web of a strip shaped film laminate such that an angle θ of the web with respect to the feeding direction becomes θ=0, and based on such understanding, proposes a continuous manufacturing system of display panels including a lamination unit for laminating together film sheets and rectangular panels both conveyed in synchronization. According to the lamination method in this system, an image of at least an edge or both edges of film sheets formed by slit lines on a carrier film conveyed to the lamination position is taken by such as a CCD camera to be visualized. Then, displacements in a feeding direction, a transverse direction and an angle are measured by comparing them with those of a case where film sheets are conveyed with θ=0. The measured displacements are represented in terms of x, y and θ values and the rectangular panels conveyed to the lamination position are checked in orientations with the x, y and θ values for adjustment of misalignment. However, it has not been specifically described how to check the rectangular panels with the measured values of the film sheets represented by x, y and θ or how to align film sheets with the rectangular panels.
The prior art documents referred to in the above descriptions are listed below.
Patent Document 1:Japanese Laid-Open Patent Publication 2002-23151APatent Document 2:Japanese Pat. No. 4371709BPatent Document 3:Japanese Pat. No. 4377964B